The prior art discloses a fiber optic cassette system comprising a rack which receives a number of like cassettes received side by side. Typically such cassettes comprise a flange about the front face which is used to secure the cassette into the rack, often by using a screw, push-pin retainer, or the like. One draw back of such prior art devices, especially in high density high density environments, is that the flange occupies space along the front of the racks which could otherwise be used to accommodate receptacles which terminate optic fiber cables.
In other implementations the cassettes are arranged horizontally, but a mounted into structures which increase tray width
Additionally, in some cross connect implementations the fiber optic cassettes are received on slidable trays. One drawback of such trays is that the cassettes are typically held entirely on the trays and as such the trays add a small yet not negligible thickness to the overall assembly which in turn affects the overall density pf the assembly.